CN103289432A - Electrophoretic particle, electrophoretic particle dispersion liquid, display medium, and display device - Google Patents

Abstract

There is provided an electrophoretic particle which contains a core material particle formed of a composition containing a resin, a nitrogen-containing heterocyclic compound having any one of an imino group, a methylol group and an alkoxymethyl group in the molecule and a heterocyclic ring having a nitrogen atom, and a coloring agent. The invention also relates to an electrophoretic particle dispersion liquid containing the electrophoretic particle, a display medium, and a display device.

Description

Electrophoresis particle, electrophoretic particle dispersion liquid, display medium and display unit

Technical field

The present invention relates to electrophoresis particle, electrophoretic particle dispersion liquid, display medium and display unit.

Background technology

For electrophoretic display medium has been carried out broad research as the indicating meter with image retentivity (being so-called memory).In these indicating systems, realize to show in the following manner: use charged electrophoresis particle in liquid, and make electrophoresis particle alternately move to the visual field and the back side of cell (cell) (it has such structure: two electrode base boards of stack and be enclosed in electrophoresis material between these two electrode base boards with dispersion medium) by applying electric field.

For example, patent documentation JP-A-2005-227729(term used herein " JP-A " refers to " Japanese unexamined patent is open ") " a kind of electric charge control method; wherein; control the electriferous state of particle in the following manner: import organic group (substituting group that this organic group has main structure and is combined with main structure) to particle surface; and to the substituting group kind; at least a condition in the bond number of being combined with main structure and the binding site sets so that the electronic localizationization in the main structure, thereby the electriferous state of control particle " and " making main structure have the part of πDian Zi delocalization " proposed.

Patent documentation JP-A-2006-106596 has proposed " particle that is used for display medium; described particle is formed in information and shows with the display medium that uses in the flat board; show information in the following manner: enclose display medium between two substrates (at least one substrate is transparent); and by apply electric field to display medium described display medium is moved; be that 450nm or littler silicon dioxide microparticle cover the particle surface that the information demonstration is used with the display medium that uses in the flat board by sol/gel method particle diameter wherein ", and proposition " carry out surface treatment to apply a certain amount of electric charge with melamine resin ".

Patent documentation JP-A-2009-223080 has proposed " but a kind of charged particle; it obtains in the following manner: in the presence of condensing agent; the carboxyl that makes the particle that has carboxyl and vinyloxy group in its surface directly carries out the amido bonding with the amino of the compound with amino and functional group, but wherein has the amido of functional group and the surface that aforesaid vinyloxy group is bonded directly to charged particle ".

Summary of the invention

One object of the present invention is to provide a kind of makes it begin the high electrophoresis particle of voltage (hereinafter, this voltage is called " threshold voltage ") when mobile by electric field.

Above problem is resolved by following content:

＜1〉a kind of electrophoresis particle comprises:

The core material particle that is formed by composition, wherein said composition contains resin, nitrogen-containing heterocycle compound and tinting material, and this nitrogen-containing heterocycle compound has any one in imino-, methylol and the alkoxy methyl and has the heterocycle of nitrogen atom in molecule.

＜2〉according to＜1〉electrophoresis particle,

Wherein said nitrogen-containing heterocycle compound is selected from the group that is made of melamine compound and guanamines compound, has in imino-, methylol and the alkoxy methyl any one in each comfortable molecule of wherein said melamine compound and guanamines compound.

＜3〉according to＜1〉electrophoresis particle,

The surface-coated cap rock of described core material particle covers,

Wherein said tectum is formed by the composition that contains resin, and described resin has the close dispersion medium part that dissolves in the dispersion medium that wherein is dispersed with electrophoresis particle and is insoluble to thin dispersion medium part in the dispersion medium that wherein is dispersed with electrophoresis particle.

＜4〉according to＜3〉electrophoresis particle,

Described tectum is formed by the composition that contains copolymer resin, the polymeric component that wherein said multipolymer comprises the polymeric component with organosilicon chain at least or has the polymeric component of alkyl chain and have the charging property group.

＜5〉according to＜1〉electrophoresis particle,

Wherein based on the total amount of core material particle, the content of described nitrogen-containing heterocycle compound is more than or equal to 0.5 quality % and is less than or equal to 50 quality %.

＜6〉according to＜1〉electrophoresis particle,

Wherein said core material particle is the core material particle that the resin crosslinks product by the described composition that contains resin, nitrogen-containing heterocycle compound and tinting material constitutes.

＜7〉according to＜3〉electrophoresis particle,

Wherein said tectum is the tectum that the resin crosslinks product by the described composition that contains described resin constitutes.

＜8〉a kind of electrophoretic particle dispersion liquid comprises:

Dispersion medium and

Be scattered in the electrophoresis particle in the described dispersion medium,

Wherein said electrophoresis particle is according to＜1〉electrophoresis particle.

＜9〉according to＜8〉electrophoretic particle dispersion liquid,

Wherein said dispersion medium contains the low solvent of specific inductivity.

＜10〉a kind of display medium comprises:

A pair of substrate, wherein at least one has light transmission, and

According to＜8〉electrophoretic particle dispersion liquid, it is closed between the described a pair of substrate.

＜11〉a kind of display medium comprises:

Pair of electrodes, wherein at least one has light transmission, and

Have according to＜8〉the zone of electrophoretic particle dispersion liquid, described zone is closed between the described pair of electrodes.

＜12〉a kind of display unit comprises:

According to＜10〉display medium, and

Voltage applying unit, it applies voltage between a pair of substrate of described display medium.

＜13〉a kind of display unit comprises:

According to＜11〉display medium, and

Voltage applying unit, it applies voltage between the pair of electrodes of described display medium.

According to the＜1 〉,＜2,＜3 and＜4〉aspect, have in the tectal electrophoresis particle at the core material particle, compare with the situation that does not contain nitrogen-containing heterocycle compound in the core material particle, the electrophoresis particle with high threshold voltage can be provided.

According to the＜5〉aspect, compare with the situation outside the content of nitrogen-containing heterocycle compound is in above-mentioned scope, the electrophoresis particle with high threshold voltage can be provided.

According to the＜6〉aspect, can't help the situation that the resin crosslinks product constitutes with the core material particle and compare, the electrophoresis particle with high threshold voltage can be provided.

According to the＜7〉aspect, can't help the situation that the resin crosslinks product constitutes with tectum and compare, the electrophoresis particle with high threshold voltage can be provided.

According to the＜8〉aspect, have in the tectal electrophoresis particle at the core material particle, compare with having used the situation that in the core material particle, does not contain the electrophoresis particle of nitrogen-containing heterocycle compound, the electrophoretic particle dispersion liquid of the electrophoresis particle that wherein is dispersed with high threshold voltage can be provided.

According to the＜9〉aspect, have in the tectal electrophoresis particle at the core material particle, with used the situation that in the core material particle, does not contain the electrophoresis particle of nitrogen-containing heterocycle compound and compared, even when use contains the dispersion medium of low-k solvent, also can provide the electrophoretic particle dispersion liquid of the electrophoresis particle that contains high threshold voltage.

According to the＜10 〉,＜11,＜12 and＜13〉aspect, have in the tectal electrophoresis particle at the core material particle, with used the situation that in the core material particle, does not contain the electrophoresis particle of nitrogen-containing heterocycle compound and compared, can provide display medium and the display unit that can realize such demonstration: in described demonstration, be inhibited by the low display defect that causes of the threshold voltage of electrophoresis particle.

Description of drawings

Fig. 1 is the synoptic diagram according to the display unit of exemplary,

The figure of particle Move Mode when Fig. 2 A and 2B apply voltage for typically showing between the substrate according to the display unit of exemplary,

Wherein

10 expression display unit, 12 expression display mediums, 16 expression voltage applying units, 18 expression control units, 20 expression display base plates, 22 expression back substrates, 24 expression distance members, 34 expression particle groups, 36 expression reflective particle groups, 38 express support for substrate, 40 presentation surface electrodes, 42 presentation surface layers, 44 express support for substrate, 46 expression backplates, 48 presentation surface layers, and 50 expression dispersion medium.

Embodiment

Hereinafter will be described an exemplary according to the present invention.

[electrophoresis particle]

Electrophoresis particle in the exemplary comprises core material particle (hereinafter being called " core particle ") and covers the tectum on core particle surface.

Core particle is formed by such composition, said composition contains resin, nitrogen-containing heterocycle compound (hereinafter being called " nitrogen-containing heterocycle compound ") and tinting material, and wherein said nitrogen-containing heterocycle compound has any one in imino-, methylol and the alkoxy methyl and has the heterocycle of nitrogen atom in molecule.Particularly, core particle preferably by containing resin, being selected from least a nitrogen-containing heterocycle compound in the group that is made of melamine compound and guanamines compound and the composition of tinting material forms, has any one in imino-, methylol and the alkoxy methyl in each comfortable molecule of wherein said melamine compound and guanamines compound.

On the other hand, tectum is formed by the composition that contains resin, and described resin has the close dispersion medium part that dissolves in the dispersion medium that wherein is dispersed with electrophoresis particle and is insoluble to thin dispersion medium part in the dispersion medium that wherein is dispersed with electrophoresis particle.Particularly, tectum is preferably formed by the composition that contains copolymer resin, the polymeric component that wherein said multipolymer contains the polymeric component with organosilicon chain at least or has the polymeric component of alkyl chain and have the charging property group.

In passing, in these polymeric components, come from hydrophobicity position after the polymerization of hydrophobicity polymeric component (as have the polymeric component of organosilicon chain or have the polymeric component of alkyl chain) corresponding to close dispersion medium part, and come from wetting ability position after the polymerization of hydrophilic polymer component corresponding to thin dispersion medium part.

In the electrophoresis particle according to this exemplary, threshold voltage uprises because of above-mentioned structure.The reason of this situation is unclear, but infers it is owing to following reason: have nitrogen-containing heterocycle compound in the core particle and cover core particle with tectum, therefore a large amount of electric charges are applied to electrophoresis particle.According to this structure, when being used in combination the electrophoresis particle of two or more homopolarities, realize the migration of each electrophoresis particle easily independently, and (for example) is easy to realize multicolor displaying in single pixel.

Particularly, though reason it be unclear that, but, (for example containing low-k, 5.0 under the situation of solvent or lower specific inductivity), be difficult to give a large amount of electric charges by the charging property group of electrophoresis particle to the dispersion medium that is used for the dispersion electrophoresis particle, and the threshold voltage of electrophoresis particle is difficult to raise.Even in this case, can be effective therefore because above structure raises still according to the threshold voltage of the electrophoresis particle of this exemplary.

Adopt display medium and the display unit of the electrophoresis particle of this exemplary can realize such demonstration: wherein, to be inhibited because the quantity of electric charge of electrophoresis particle reduces the display defect (for example, display density reduction, colour mixture show) that causes.

Therefore in addition, in the electrophoresis particle according to exemplary, the ratio of opposite polarity particle is easy to because above structure reduces, and easily realizes the demonstration that display defect wherein (for example, display density reduces, colour mixture show) is inhibited.

Hereinafter will describe the electrophoresis particle according to exemplary in detail.

(core particle)

Core particle is by containing resin (hereinafter being called " core particle resin "), having the nitrogen-containing heterocycle compound of nitrogen atom heterocycle and the composition of tinting material forms.

Particularly, core particle can be by the composition that contains resin, nitrogen-containing heterocycle compound and tinting material (namely, contain the nitrogen-containing heterocycle compound that is scattered in the resin and the composition of tinting material) constitute, it perhaps can be the resin crosslinks product (that is the composition that, contains the tinting material in the resin crosslinks product that is scattered in resin and nitrogen-containing heterocycle compound) that contains the composition of resin, nitrogen-containing heterocycle compound and tinting material.

Particularly, under the situation that core particle is made of resin crosslinks product (containing the resin crosslinks product of resin and nitrogen-containing heterocycle compound and the composition of tinting material), the threshold voltage that electrophoresis particle is endowed a large amount of electric charges and electrophoresis particle is easy to raise.In addition, the ratio of opposite polarity particle is easy to reduce in the electrophoresis particle.

-core particle resin-

As the core particle resin, with regard to the preparation of electrophoresis particle, preferably water soluble resin or spirit-soluble resin.In passing, water-soluble or pure solvability refer to that under 25 ℃ the meltage of the material of object material in water or alcohol is more than the 1 quality %.

When forming the resin crosslinks product by nitrogen-containing heterocycle compound, core particle preferably has reactive functional groups (for example, hydroxyl, carboxylic acid group etc.) with resin.

Core particle can be that the charging property resin ((for example has the charging property group with resin, polarizable functional group, polar group) resin), perhaps can be non-charging property resin (resin that does not have the charging property group), but with regard to improving the quantity of electric charge, resin be preferably the charging property resin.

As the charging property resin, for example, can enumerate the homopolymer of the polymeric component with charging property group and have the polymeric component of charging property group and the multipolymer that does not have the polymeric component of charging property group.

On the other hand, as no electric resin, for example, can enumerate the homopolymer of the polymeric component with charging property group.

These polymeric components can use separately, perhaps can two or more be used in combination.

As charging property group (for example, polar group, polarizable functional group), can exemplify basic group and acidic-group.

Basic group (hereinafter being called cation group) as the charging property group for example comprises amino and quaternary ammonium group (salt that also comprises these groups).These cation groups tend to provide positive charge polarity to particle.

Acidic-group (hereinafter being called anionic group) as the charging property group for example comprises phenolic group, carboxyl, carboxylic acid foundation, sulfonic group, sulfonic acid foundation, phosphate group, phosphoric acid foundation and tetraphenyl boryl (salt that also comprises these groups).These anionic groups tend to provide negative charge polarity to particle.

Except above-mentioned, also can exemplify fluorine-based, phenyl and hydroxyl as the charging property group.

Hereinafter every kind of polymeric component will be described.

In the following description, " (methyl) acrylate " is intended to comprise " acrylate " and " methacrylic ester ".

As the polymeric component with cation group (hereinafter being called the cationoid polymerisation component), exemplify following material.Particularly, can exemplify: (methyl) acrylate with aliphatic amino, as (methyl) vinylformic acid N, N-dimethylaminoethyl, (methyl) vinylformic acid N, N-lignocaine ethyl ester, (methyl) vinylformic acid N, N-dibutylamino ethyl ester, (methyl) vinylformic acid N, N-hydroxyethylamino ethyl ester, (methyl) vinylformic acid N, N-ethylamino ethyl ester, (methyl) vinylformic acid N-octyl group-N-ethylamino ethyl ester and (methyl) vinylformic acid N, N-two own amino ethyl esters; The vinyl monomer that is replaced by aromatics with nitrogen-containing group is as dimethylamino vinylbenzene, diethylamino vinylbenzene, dimethylamino methyl vinylbenzene and dioctyl amino-benzene ethene; Nitrogenous vinyl ether monomers is as vinyl-N-ethyl-N-phenyl amino ethyl ether, vinyl-N-butyl-N-phenyl amino ethyl ether, trolamine divinyl ether, vinyl diphenyl amino ethyl ether, N-vinyl hydroxyethylbenzene methane amide and m-aminophenyl base vinyl ether; Pyroles is as vinyl amine and N-vinyl pyrrole; The pyrroline class is as N-vinyl-2-pyrroline and N-vinyl-3-pyrroline; Pyrrolidines is as N-ethenyl pyrrolidone, ethenyl pyrrolidone amino ethers and N-vinyl-2-Pyrrolidone; Imidazoles is as N-vinyl-glyoxal ethyline; Imidazolines is as N-vinyl imidazole quinoline; Indoles are as N-vinyl indoles; Dihydroindolines is as N-vinyl indoline; Carbazoles is as N-vinylcarbazole and 3,6-, two bromo-N-vinylcarbazole; Pyridines is as 2-vinyl pyridine, 4-vinylpridine and 2-methyl-5-vinylpyrine; Piperidines is as (methyl) acryl piperidines, N-vinyl piperidone and N-vinyl piperazine; Quinoline is as 2-vinylquinoline and 4-vinylquinoline; Pyrazoles is as N-vinyl pyrazoles and N-vinyl pyrazoles quinoline; The oxazole class is as 2-Yi Xi Ji oxazole; Yi is Ji the oxazine class, as 4-Yi Xi Ji oxazine and (methyl) vinylformic acid morpholino ethyl ester.

The cationoid polymerisation component can form quaternary ammonium salt by chlorination before or after polymerization.For example, by making the reaction of cation group and haloalkane or tosylate obtain quaternary ammonium salt.

As the polymeric component with anionic group (hereinafter being called the anionoid polymerization component), for example, can enumerate polymeric component with carboxylic acid group, have sulfonic polymeric component and have the polymeric component of phosphate.

Example (for example) with polymeric component of carboxylic acid group comprise (methyl) vinylformic acid, Ba Dousuan, methylene-succinic acid, toxilic acid, fumaric acid, citraconic acid, they acid anhydrides, they mono alkyl ester, have vinyl ether (as propyloic vinyl ether, carboxylic propyl vinyl ether) and their salt of carboxyl.

Example (for example) with sulfonic polymeric component comprising: styrene sulfonic acid, 2-acrylamido-2-methyl propane sulfonic acid, (methyl) vinylformic acid 3-sulfo group propyl ester, two (3-sulfopropyl) itaconic esters and their salt.Except above-mentioned substance, as having sulfonic polymeric component, can also exemplify the acrylic acid sulfuric acid monoester of 2-hydroxyethyl (methyl) and salt.

Example (for example) with polymeric component of phosphate comprising: vinyl phosphoric acid, vinyl phosphate, acid phosphorus oxygen ethyl (methyl) acrylate, acid phosphorus oxygen propyl group (methyl) acrylate, two (methylacryoyloxyethyl) phosphoric acid ester, two phenyl-2-methylacryoyloxyethyl phosphoric acid ester, two phenyl-2-acrylyl oxy-ethyl phosphoric acid ester, dibutyl-2-methylacryoyloxyethyl phosphoric acid ester, dibutyl-2-acrylyl oxy-ethyl phosphoric acid ester and dioctyl-2-(methyl) acrylyl oxy-ethyl phosphoric acid ester.

The anionoid polymerization component can form ammonium salt by chlorination before or after polymerization.For example, by making the reaction of anionic group and tertiary amine or quaternary ammonium hydroxide obtain ammonium salt.

Example (for example) with fluorine-based polymeric component comprises (methyl) acrylate monomer with fluorine atom.Particularly, can exemplify (methyl) vinylformic acid trifluoro ethyl ester, (methyl) vinylformic acid five fluorine propyl ester, (methyl) vinylformic acid perfluor ethyl ester, (methyl) vinylformic acid perfluoro butyl ethyl ester, (methyl) vinylformic acid perfluoro capryl ethyl ester, (methyl) vinylformic acid perfluor decyl ethyl ester, (methyl) vinylformic acid trifluoromethyl trifluoro ethyl ester and (methyl) vinylformic acid hexafluoro butyl ester.

Example (for example) with polymeric component of phenyl comprising: vinylbenzene, (methyl) vinylformic acid phenoxy group glycol ester and (methyl) vinylformic acid 2-hydroxyl-3-phenoxy group propyl ester.

Example (for example) with polymeric component of hydroxyl comprising: hydroxyalkyl (methyl) acrylate (as, (methyl) Hydroxyethyl acrylate, (methyl) Propylene glycol monoacrylate), allyl alcohol and polyethyleneglycol (methyl) acrylate.Except above-mentioned, can also exemplify such polymeric component: the polymeric component that the monomer copolymerizable by will having glycidyl and open loop subsequently obtain and the monomer polymerization by will having tert.-butoxy and hydrolysis subsequently are to import the polymeric component that the OH base is obtained.

As the polymeric component that does not have the charging property group, can enumerate nonionic polymeric component (non-ionic type polymeric component), for example can enumerate (methyl) acrylamide, vinylcarbazole, vinylchlorid, vinylidene chloride and the vinyl pyrrolidone of (methyl) vinyl cyanide, (methyl) alkyl acrylate, (methyl) acrylamide, ethene, propylene, divinyl, isoprene, iso-butylene, the replacement of N-dialkyl group.

With in the resin, in the total polymerization component, the shared mol ratio of polymeric component with charging property group is preferably more than or equals 1 mole of % and be less than or equal to 98 moles of % at core particle, and more preferably more than or equal to 5 moles of % and be less than or equal to 95 moles of %.

Core particle is preferably more than with the weight-average molecular weight of resin or equals 1,000 and be less than or equal to 1,000,000, and more preferably more than or equal to 10,000 and be less than or equal to 200,000.

-nitrogen-containing heterocycle compound-

Nitrogen-containing heterocycle compound is not as the polymeric component of resin, but the compound that comprises separately or comprise as crosslinking component, and it has the functional group that can carry out condensation reaction with contained resin in the core particle.

As nitrogen-containing heterocycle compound, for example, can enumerate the melamine compound and the guanamines compound that have in imino-, methylol and the alkoxy methyl any one in each comfortable molecule.

Based on core particle integral body, the content of these nitrogen-containing heterocycle compounds is preferably more than or equals 0.5 quality % and be less than or equal to 50 quality %, perhaps for more than or equal to about 0.5 quality % and be less than or equal to about 50 quality %, more preferably more than or equal to 1 quality % and be less than or equal to 30 quality %, perhaps for more than or equal to about 1 quality % and be less than or equal to about 30 quality %, and more preferably more than or equal to 2 quality % and be less than or equal to 20 quality %, perhaps for more than or equal to about 2 quality % and be less than or equal to about 20 quality %.

When the content of nitrogen-containing heterocycle compound was in above-mentioned scope, threshold voltage from electrophoresis particle to electrophoresis particle that give a large amount of electric charges and uprised easily, and the ratio of the particle of opposite polarity also is easy to reduce in the electrophoresis particle.

Consider that from the angle of preparation electrophoresis particle nitrogen-containing heterocycle compound is preferably water-soluble cpds or pure soluble compound.

The guanamines compound

The guanamines compound is the compound with guanamines skeleton (structure), for example, can enumerate acetylguanamine, benzoguanamine, formoguanamine, steroid guanamines, spiral shell guanamines and cyclohexyl guanamines.

As the guanamines compound, compound and at least a polymer thereof of following formula (A) expression are particularly preferred.Here, polymer is to carry out the oligopolymer that polymerization obtains by the compound with formula (A) expression as structural unit, and the polymerization degree is 2 to 200, is preferably 2 to 100.(A) compound represented of formula can use separately or can two or morely unite use.Particularly, when the compound of formula (A) expression used as two or more mixtures, when perhaps using as the polymer (oligopolymer) of structural unit with this compound, its solubleness in solvent was improved.

In formula (A), R ₁Expression has the straight or branched alkyl of 1 to 10 carbon atom, the replacement with 6 to 10 carbon atoms or unsubstituted phenyl or has replacement or the unsubstituted alicyclic hydrocarbon radical of 4 to 10 carbon atoms; R ₂To R ₅Represent independently of one another hydrogen atom ,-CH ₂-OH or-CH ₂-O-R ₆And R ₆Expression has the straight or branched alkyl of 1 to 10 carbon atom.

In formula (A), by R ₁The alkyl of expression has 1 to 10 carbon atom, preferably has 1 to 8 carbon atom, and more preferably has 1 to 5 carbon atom.Alkyl can be straight chain or side chain.

In formula (A), by R ₁The phenyl of expression has 6 to 10 carbon atoms, and preferably has 6 to 8 carbon atoms.As the substituent example that is substituted on the phenyl, for example can enumerate methyl, ethyl and propyl group.

In formula (A), by R ₁The alicyclic hydrocarbon radical of expression has 4 to 10 carbon atoms, and preferably has 5 to 8 carbon atoms.As the substituent example that is substituted on the alicyclic hydrocarbon radical, for example can enumerate methyl, ethyl and propyl group.

In formula (A), by R ₂To R ₅Represent separately-CH ₂-O-R ₆In, by R ₆The alkyl of expression has 1 to 10 carbon atom, preferably has 1 to 8 carbon atom and more preferably have 1 to 6 carbon atom.Alkyl can be straight or branched, for example can enumerate to be preferably methyl, ethyl and butyl.

Compound by formula (A) expression is preferably such compound, wherein R especially ₁Expression has replacement or the unsubstituted phenyl of 6 to 10 carbon atoms; R ₂To R ₅Expression-CH independently of one another ₂-O-R ₆And R ₆Be preferably selected from methyl and normal-butyl.

For example, by using guanamines and formaldehyde, come the compound shown in the synthesis type (A) by currently known methods (for example, Japanization association compiles, experimental chemistry lecture (Experimental Chemistry Course), the 4th edition, the 28th volume, the 430th page).

Specific examples as the compound of being represented by formula (A) hereinafter show exemplary compounds (A)-1 to (A)-42, but exemplary is not limited thereto.Following specific examples is monomer, but can use with the polymer (oligopolymer) of these monomers as structural unit.In following exemplary compounds, " Me " refers to methyl, and " Bu " refers to butyl, and " Ph " expression phenyl.

The commercially available prod of the compound of representing as (A) formula, for example, can enumerate SUPER BECKAMINE (R) L-148-55, SUPER BECKAMINE (R) 13-535, SUPER BECKAMINE (R) L-145-60, SUPER BECKAMINE (R) TD-126(by the product of DIC company preparation), NIKALAC MW-390, NIKALAC BL-60 and NIKALAC BX-4000(be by the product of Sanwa KCC preparation).

Behind the compound (comprising polymer) or purchase commercially available prod that synthetic (A) formula is represented, in order to remove the influence of residual solvent, they can be dissolved in the The suitable solvent (as toluene, dimethylbenzene or ethyl acetate) and with distilled water or ion-exchange water washing, perhaps can handle to remove by spent ion exchange resin.

Melamine compound

Melamine compound is the compound with trimeric cyanamide skeleton (structure), and compound and at least a polymer thereof especially preferably represented by following formula (B).Here, (A) is similar with formula, and polymer is that the compound by use formula (B) expression carries out the oligopolymer that polymerization obtains as structural unit, and the polymerization degree is 2 to 200, is preferably 2 to 100.(B) compound or its polymer represented of formula can use separately, perhaps can two or morely unite use.In addition, the compound of formula (B) expression can be used in combination with compound or its polymer that (A) formula is represented.Particularly, when (B) compound represented of formula used as two or more mixtures, when perhaps using as the polymer (oligopolymer) of structural unit with this compound, its solubleness in solvent was improved.

In formula (B), R ⁶To R ¹¹Represent independently of one another hydrogen atom ,-CH ₂-OH ,-CH ₂-O-R ¹²Or-O-R ¹²And R ¹²Expression can be the alkyl with 1 to 5 carbon atom of side chain.As alkyl, for example can enumerate methyl, ethyl and butyl.

For example, by using trimeric cyanamide and formaldehyde, the compound that comes synthetic (B) formula to represent by any known process (with experimental chemistry lecture (Experimental Chemistry Course), the 4th edition, the 28th volume, the similar mode of melamine resin described in the 430th page are synthesized).

As the specific examples of the compound of being represented by (B) formula, exemplary compound (B)-1 is shown below to (B)-8, but exemplary is not limited thereto.Following specific examples illustrates with the form of monomer, but also can use to have these compounds as the polymer (oligopolymer) of structural unit.

Commercially available prod as the compound of being represented by (B) formula, for example, can enumerate SUPER MELAMINE No.90(by Nichiyu KCC preparation), SUPER BECKAMINE (R) TD-139-60(is by the preparation of DIC company), YUBAN2020(is by the preparation of Mitsui KCC), SUMITEX RESIN M-3(is by the preparation of Sumitomo KCC), NIKALAC MW-390 and NIKALAC MW-30(be by the preparation of Sanwa KCC).

Behind the compound (comprising oligopolymer) or purchase commercially available prod that synthetic (B) formula is represented, in order to remove the influence of residual solvent, they can be dissolved in the The suitable solvent (as toluene, dimethylbenzene or ethyl acetate), and with distilled water or ion-exchange water washing, perhaps can be by using ion exchange resin treatment to remove.

Other nitrogen-containing heterocycle compound

As other nitrogen-containing heterocycle compound, for example can enumerate those compounds that obtain by the triazine ring with other nitrogen heterocyclic ring substituted melamine compound and guanamines compound.As other nitrogen heterocyclic ring, for example can enumerate: pyrrole ring, imidazole ring, pyrazoles ring, oxazole ring, furazan ring, piperidine ring, pyridine ring, pyrazine ring, piperazine ring, pyrimidine ring, pyridazine ring, morpholine ring, pyrrolidine ring, benzazole ring, indolizine ring, indole ring, indazole ring, purine skeleton, quinolizine ring, quinoline ring, diaza naphthalene nucleus, naphthyridines ring, phthalazines ring, naphthyridines ring, quinoxaline ring, quinazoline ring, cinnolines ring, pteridine ring, carbazole ring, carboline ring, perimidine ring, phenanthroline ring and anthracene aziridine (anthyridine) ring.

Because melamine compound, guanamines compound and other above nitrogen-containing heterocycle compound contain any at least in imino-, methylol and the alkoxy methyl in molecule, thus they may with contained resin generation condensation reaction in the core particle.

Specifically, for example, can carry out the condensation reaction of any representative in the following reaction formula.

1)>NH+>NCH ₂OH→>NCH ₂N<+H ₂O

2) 2〉NCH ₂OH(is under acidic conditions) → NCH ₂N＜+HCHO+H ₂O

3)>NCH ₂OH+NH→>NCH ₂N<+H ₂O

4) 2〉NCH ₂OH(is under alkaline condition) → CH ₂OCH ₂N＜+H ₂O

5)〉NCH ₂OH+-OH(is under solutions of weak acidity) → NCH ₂O-+H ₂O

6)〉NCH ₂OH+-COOH(is under solutions of weak acidity) → NCH ₂OCO-+H ₂O

7)〉NCH ₂OH+-CONH ₂(under solutions of weak acidity) →〉NCH ₂NHCO-+H ₂O

8)〉NCH ₂OR+-OH(is under acidic conditions) → NCH ₂O-+ROH

9)〉NCH ₂OR+-COOH(is under acidic conditions) → NCH ₂OCO-+ROH

10)〉NCH ₂OR+-CONH ₂(under acidic conditions) →〉NCH ₂NHCO-+ROH

The nitrogen-containing heterocycle compound that may cause these condensation reactions has such advantage: because by simple operations such as heat after the core particle granulation, these compounds are because of self condensation reaction resinifying, therefore perhaps by realizing three-dimensional cross-linkedly with resin generation condensation reaction with core particle, the degree of freedom of preparation increases.In addition, they also have such advantage: owing to compare with the compound that may cause free radical reaction, the increase of viscosity and the reduction of solubleness take place hardly when the core particle granulation, therefore restricted less by due to the solvent.In addition, compare with the compound that may cause free radical reaction, also advantageously, increase and the non-homogeneous reaction of unreacted reactant take place hardly.

Particularly, melamine compound, guanamines compound and other above nitrogen-containing heterocycle compounds can easily have polyfunctional group, and the resin crosslinks structure of core particle is easy to strengthen.In passing, in many cases, make vinyl have multifunctional meeting and cause synthesis condition complicated and strict, and cause the increase of manufacturing cost.

-tinting material-

As tinting material, can exemplify organic or inorganic pigment and oil base dyestuff.For example, can enumerate: magnetic, as magnetite and ferrite; And known tinting material, as carbon black, titanium oxide, magnesium oxide, zinc oxide, CuPc base cyan coloured material, azo-group yellow coloring material, the pinkish red coloured material of azo-group, the pinkish red coloured material of quinacridine ketone group, red colored material, green coloring material and blue-colored material.Especially, aniline blue, Chalcoyl indigo plant, chrome yellow, ultramarine blue, Du Pont's oil red, quinoline yellow, protochloride methyl indigo plant, phthalocyanine blue, Victoria Green WPB oxalate, dim, rose-red, C.I. pigment red 4 8:1, C.I. pigment red 122, C.I. Pigment red 57:1, C.I. Pigment Yellow 73 97, C.I. pigment Blue 15: 1 and the C.I. pigment Blue 15: 3 is representative tinting material.

Based on the resin in the core particle, the use level of tinting material is preferably more than or equals 10 quality % and be less than or equal to 99 quality %, and more preferably more than or equal to 30 quality % and be less than or equal to 99 quality %.

-other compounding ingredients-

Core particle can contain other compounding ingredient.

As other compounding ingredient, for example can enumerate charge control material and magneticsubstance.

As charge control material, can use the materials known as the electrofax tinter material, example comprises cetylpyridinium chloride, quaternary ammonium salt (as BONTRON P-51, BONTRON P-53, BONTRON E-84 and the BONTRON E-81(product by the preparation of Orient Chemical Co., Ltd)), Whitfield's ointment is that metal complex, phenol are condenses, tetraphenyl based compound, metal oxide particle and had carried out the surface-treated metal oxide particle with polytype coupling agent.

As magneticsubstance, the inorganic or organo-metallic material that uses colorant to coat as required.Transparent Magnetic Materials (particularly transparent organo-metallic material) suppresses the colour developing of tinting pigment hardly, and compare its proportion with inorganic magnetic material little, therefore very preferably uses them.

As painted magneticsubstance (material that colorant coats), for example can be set forth in the painted magnetic powder of disclosed small particle size among the patent documentation JP-A-2003-131420.Use so painted magneticsubstance: it contains magnetic-particle as the nuclear core and is layered in the lip-deep pigmented layer of magnetic-particle.As pigmented layer, magnetic-particle can still preferably use (for example) optical interference film with coatings opaquely such as pigment.Optical interference film is (as SiO by colourless material ₂Or TiO ₂) form, its thickness equates with optical wavelength, and comes optionally catoptrical wavelength by the interference of light in the film.

The preferable configuration of-core particle-

As above-mentioned core particle, especially preferred is to contain 1) styrene-propene acid resin, 2) hydroxyalkyl-ammonium resin and 3) structure of acrylic resin.

As the structure of above-mentioned core particle, especially preferably contain the melamine compound of formula (B) expression as nitrogen-containing heterocycle compound.

The particularly preferred structure of above-mentioned core particle contains the cross-linking products that core particle is used resin and nitrogen-containing heterocycle compound.

(tectum)

Tectum is formed by the composition that contains such resin, and described resin has the close dispersion medium part that dissolves in the dispersion medium that wherein is dispersed with electrophoresis particle and is insoluble to thin dispersion medium part (hereinafter this resin is known as " tectum resin ") in the dispersion medium that wherein is dispersed with electrophoresis particle.

Here, tectum partly refers to such part with the close dispersion medium of resin: the polymeric component that constitutes this parent's dispersion medium part dissolves in the dispersion medium.Dissolve in dispersion medium and refer to that under 25 ℃ subject material is dissolved 1 quality % or more in dispersion medium.

On the other hand, tectum is partly represented such part with the thin dispersion medium of resin: the polymeric component that constitutes this thin dispersion medium part is insoluble to be dredged in the medium.Be insoluble to dispersion media and refer to that under 25 ℃ subject material is dissolved 0.01 quality % or more in dispersion medium.

Consider that from the angle of preparation electrophoresis particle the preferred tectum of formation like this makes tectum dissolve in (that is, before covering core particle) in the dispersion medium as resin separately with resin, and is insoluble in the dispersion medium after covering core particle.

In order to realize this structure, for example, can exemplify make tectum with the method for resin crosslinks, with described resin-bonded to the method on core particle surface and make the resin multipoint adsorption in the lip-deep method of core particle.

-tectum resin-

As the tectum resin, particularly, for example, can exemplify the resin that is made of following multipolymer, this multipolymer contains: have the polymeric component of organosilicon chain or have alkyl chain polymeric component, have the polymeric component of charging property group and other polymeric component as required.

Tectum can be by comprising that the non-crosslinked resin constitutes or can constituting by the cross-linking products that comprises resin.

That is, tectum can be formed or can be formed by the resin crosslinks product of the composition that contains resin by the composition that contains resin.

Particularly, under the situation that tectum is made of the resin crosslinks product, threshold voltage from electrophoresis particle to electrophoresis particle that give a large amount of electric charges and is easy to raise.And the ratio of the particle of opposite polarity also is easy to reduce in the electrophoresis particle.

As making tectum with the method for resin crosslinks, can illustrate: make the method for resin crosslinks by making the have reactive group polymeric component polymerization of (crosslinked group), and make the method for resin crosslinks by additionally adding linking agent.

Polymeric component with organosilicon chain

Polymeric component (monomer with organosilicon chain) with organosilicon chain for example is the macromonomer with organosilicon chain.Particularly, for example, can be set forth in the dimethyl organosilane monomer (silicoorganic compound of following structural formula (1) expression) that an end has (methyl) acrylate group, for example, SILAPLANE FM-0711, FM-0721, FM-0725(are by the preparation of Chisso company) and X-22-174DX, X-22-2426, X-22-2475(prepared by Shin-Etsu KCC).

Structural formula (1)

In structural formula (1), R ₁Expression hydrogen atom or methyl; R ₁' expression hydrogen atom or have the alkyl of 1 to 4 carbon atom; N represent natural number (for example, more than or equal to 1 and be less than or equal to 1,000, be preferably more than or equal 3 and be less than or equal to 100), and x represents 1 to 3 integer.

Polymeric component with alkyl chain

As the polymeric component with alkyl chain, for example can enumerate chain alkyl (methyl) acrylate.As chain alkyl (methyl) acrylate, those of alkyl chain that preferably have 4 or more carbon atoms, and the example comprises (methyl) butyl acrylate, (methyl) Ethyl acrylate, (methyl) 2-EHA, (methyl) dodecylacrylate and (methyl) vinylformic acid stearyl.

In passing, chain alkyl refers to that (for example) has about 4 alkyl chains to about 30 carbon atoms.

Polymeric component with charging property group

Polymeric component with charging property group is identical with the polymeric component with charging property group described in the polymeric component of resin with core particle.

Other polymeric component

As other polymeric component, the polymeric component with charging property group and the polymeric component with reactive group can be shown.

The polymeric component that does not have the charging property group is identical with the polymeric component that does not have the charging property group described in the polymeric component of resin with core particle.

As the polymeric component with reactive group, for example, glycidyl (methyl) acrylate with epoxy group(ing) can be shown, isocyanates monomer (as KARENZ AOI (2-isocyanic ester ethyl propenoate) and the KARENZ MOI (2-isocyanic ester Jia Jibingxisuanyizhi) by the preparation of Showa Denko K.K. Co., Ltd.) with isocyanate group, isocyanates monomer (as by KARENZ MOI-BM methacrylic acid [2-[o-(the 1'-methyl propylidene amino) carboxyamino] ethyl ester of Showa Denko K.K. Co., Ltd. preparation and KARENZ MOI-BP methacrylic acid [2-[(3,5-dimethyl pyrazole base) carbonylamino] ethyl ester) with blocked isocyanate base.

In passing, the isocyanate group of sealing is in the state with the substitution reaction that breaks away from by heating, and thus, the reactivity of isocyanate group is restricted, and when breaking away from substituting group by heating, isocyanate group enters the state that induces reaction.

When this polymeric component with reactive group was used the polymeric component of resin as tectum, tectum took place crosslinked with resin itself, the result, and tectum is made of the resin crosslinks product.In addition, the tectum reactive group of resin and the functional groups on core particle surface, tectum is covered by core particle.

Except as tectum with the polymeric component of resin, the polymeric component with reactive group can be added in the reaction system, as with tectum with resin linking agent different, that be used for making tectum usefulness resin crosslinks.

With in the resin, the mol ratio that the polymeric component with organosilicon chain accounts for whole polymeric components is preferably more than or equals 1 mole of % and be less than or equal to 90 moles of % at tectum, more preferably more than or equal to 5 moles of % and be less than or equal to 50 moles of %.

With in the resin, the mol ratio that the polymeric component with charging property group accounts for whole polymeric components is preferably more than or equals 10 moles of % and be less than or equal to 99 moles of % at tectum, more preferably more than or equal to 50 moles of % and be less than or equal to 95 moles of %.

With in the resin, the mol ratio that the polymeric component with reactive group accounts for whole polymeric components is preferably more than or equals 0.1 mole of % and be less than or equal to 50 moles of % at tectum, more preferably more than or equal to 0.5 mole of % and be less than or equal to 30 moles of %.

Based on the tectum resin, be used for to obtain the consumption of linking agent of resin crosslinks product excellently for more than or equal to 0.1 quality % and be less than or equal to 70 quality %, more preferably more than or equal to 1 quality % and be less than or equal to 50 quality %.

Tectum is preferably more than with the weight-average molecular weight of resin or equals 500 and be less than or equal to 1,000,000, more preferably more than or equal to 1,000 and be less than or equal to 1,000,000.

-other compounding ingredient-

Tectum can contain other compounding ingredient.

As other compounding ingredient, for example can be illustrated in the modified organic silicon that has functional group on the position of side chain, main chain, end or their combination.The example of functional group comprises acryl, amino, carboxyl, hydroxyl, epoxy group(ing), alkyl, phenyl, ester group, amido and ether structure group.

-tectal feature-

Based on core particle, the lip-deep tectal overlay capacity of core particle is for more than or equal to 0.00001 quality % and be less than or equal to 50 quality %, and is preferably more than or equals 0.0001 quality % and be less than or equal to 10 quality %.

-tectal preferred formation-

As above-mentioned tectal structure, especially preferably contain following resin as the tectum resin: 1) silicone macromolecule monomer, (methyl) vinylformic acid, (methyl) acrylate, the blocked isocyanate resin, 2) silicone macromolecule monomer, hydroxyalkyl (methyl) acrylate, the blocked isocyanate resin, 3) silicone macromolecule monomer, hydroxyalkyl (methyl) acrylate, (methyl) vinylformic acid phenoxy group aklylene glycol, the blocked isocyanate resin, and 4) the silicone macromolecule monomer, hydroxyalkyl (methyl) acrylate, contain amino (methyl) acrylate, the blocked isocyanate resin.

(feature of electrophoresis particle)

According to the median size (volume average particle size) of the electrophoresis particle of exemplary for (for example) more than or equal to 0.1 μ m and be less than or equal to 10 μ m, but median size selects to be not limited to this according to purposes.

With Photal FPAR-1000(dynamic light scattering size distribution measuring apparatus, made by Otsuka Electronics Co., Ltd) measure median size, and analyze with the MARQUARDT method.

(manufacture method of electrophoresis particle)

An example as the electrophoresis particle manufacture method in the exemplary following method is shown, but embodiment is not limited thereto.

At first, core particle is dissolved in first solvent with resin, nitrogen-containing heterocycle compound, tinting material and other compounding ingredients, wherein is dissolved with the mixing solutions that core particle is used resin and nitrogen-containing heterocycle compound with preparation.

Here, first solvent is the good solvent that can form disperse phase in second solvent of describing after a while (can form the poor solvent of external phase).The boiling point of first solvent is lower than the boiling point of second solvent, and first solvent is selected from the solvent that can dissolve core particle usefulness resin and nitrogen-containing heterocycle compound.

As first solvent, for example can enumerate water, Virahol (IPA), methyl alcohol, ethanol, butanols, tetrahydrofuran (THF), ethyl acetate and butylacetate.

Secondly, with mixing solutions and second solvent, stirring and the emulsification that obtains, to prepare with the emulsion of second solvent as external phase.

Wait first solvent of removing in the emulsion (drying) so that core particle resin and nitrogen-containing heterocycle compound precipitation by heating, thereby obtain core particle (being scattered in the core particle in second solvent) as granular disintegration, this granular disintegration contains aforementioned component, tinting material and other compounding ingredient.

Opposite with first solvent that can form disperse phase, second solvent is the poor solvent that can form external phase.The boiling point of second solvent is higher than first solvent, and second solvent is selected from such solvent, and wherein core particle is insoluble in this solvent with resin and nitrogen-containing heterocycle compound.

To be enumerated as second solvent for the dispersion medium of the electrophoresis particle that disperses to obtain.

Subsequently, tectum with resin and other compounding ingredient and the 3rd solvent, wherein is dissolved with the mixing solutions that tectum is used resin with preparation.

Here, the 3rd solvent also is the good solvent that can form disperse phase in second solvent (can form the poor solvent of external phase).The boiling point of the 3rd solvent is lower than second solvent, and the 3rd solvent is selected from the solvent that can dissolve tectum usefulness resin.Also preferably select the 3rd solvent from such solvent, wherein core particle is insoluble in this solvent with resin and nitrogen-containing heterocycle compound.

As the 3rd solvent, for example also can enumerate water, Virahol (IPA), methyl alcohol, ethanol, butanols, tetrahydrofuran (THF), ethyl acetate and butylacetate.

Secondly, with the mixing solutions that obtains and second solvent, stirring and the emulsification that wherein are dispersed with core particle, to prepare with the emulsion of second solvent as external phase.

Wait the 3rd solvent of removing in the emulsion (drying) by heating, so that tectum uses resin precipitated on the surface of core particle, thereby form the tectum that contains tectum resin, other compounding ingredient on the surface of core particle.

After this, under the situation that core particle and tectum are formed by the resin crosslinks product, heat-treat so that resin crosslinks.

Therefore, obtained to contain the electrophoretic particle dispersion liquid that is formed at the lip-deep tectal electrophoresis particle of core particle and contains this electrophoresis particle.

If necessary, the available dispersion medium of the electrophoresis particle of gained (for example) (solvent) dilution.In order to obtain to contain the electrophoretic particle dispersion liquid of two or more electrophoresis particles, prepare two or more dispersion liquids, mix the dispersion liquid of gained subsequently.

[electrophoretic particle dispersion liquid]

Electrophoretic particle dispersion liquid according to exemplary contains dispersion medium and the electrophoresis particle that is scattered in the dispersion medium, and this electrophoretic particle dispersion liquid contains the electrophoresis particle of with good grounds exemplary.

Dispersion medium is not particularly limited, but is preferably selected from the solvent of low-k (for example, 5.0 or littler specific inductivity, be preferably 3.0 or littler).Other solvent outside the solvent of low-k be can be used in combination as dispersion medium, but 50 volume % or more low-k solvent preferably contained.The specific inductivity of low-k solvent can record with specific inductivity meter (being made by Nihon Rufuto Co., Ltd.).

As the solvent of low-k, for example can enumerate being derived from the high boiling solvent of having of oil, as paraffinic hydrocarbon solvent, silicone oil and fluorine class I liquid I.

Preferably select the solvent of low-k with the kind of the polymeric component of resin according to the tectum of electrophoresis particle.Particularly, have the component of organosilicon chain in use as under the situation of tectum with the polymeric component of resin, preferred silicone oil is as dispersion medium.In addition, have the component of alkyl chain when use as under the situation of tectum with the polymeric component of resin, preferably select the paraffinic hydrocarbon solvent as dispersion medium.

Yet exemplary is not limited thereto.For example, even the component that has the organosilicon chain when use also can select the paraffinic hydrocarbon solvent as dispersion medium as under the situation of tectum with the polymeric component of resin.

As silicone oil, specifically can exemplify the silicone oil (for example, dimethyl silicone oil, diethyl silicone oil, methylethyl silicone oil, methylbenzene silicone oil and phenylbenzene silicone oil) that alkyl wherein is combined with siloxane bond.In the middle of these silicone oil, preferred especially dimethyl silicone oil.

As the paraffinic hydrocarbon solvent, can exemplify positive structure chain hydrocarbon (having 80 ℃ or higher boiling point) and isoparaffin class hydrocarbon with 20 or more carbon atoms.Consider security and volatility, preferably use isoparaffin.Particularly, can exemplify SHELLSOL 71(is prepared by the Shell Oil Co.), ISOPAR O, ISOPAR H, ISOPAR K, ISOPAR L, ISOPAR G and ISOPAR M(ISOPAR be the trade mark of exxon chemical company) and IP solvent (by the preparation of Idemitsu Petro Chemicals Co., Ltd.).

If necessary, can for the purpose of anti-oxidation and uv-absorbing, can add stablizer, antiseptic-germicide and sanitas in addition to according to adding acid, alkali, salt, dispersion agent, dispersion stabilizer in the electrophoretic particle dispersion liquid of exemplary.In addition, charge control agent can be added in the electrophoretic particle dispersion liquid according to exemplary.

According to display characteristic and response characteristic, differently select electrophoresis particle according to the concentration in the electrophoretic particle dispersion liquid of exemplary, but preferably more than or equal to 0.1 quality % and be less than or equal to the scope of 30 quality %.When the mix particles of different colours, overall particle preferably is in this scope.

The display medium, the light modulation medium (optic modulating device) of electrophoresis system and the liquid toner of liquid development type electrophotographic system that are used for the electrophoresis system according to the electrophoretic particle dispersion liquid of exemplary.In passing, as the display medium of electrophoresis system and the light modulation medium (optic modulating device) of electrophoresis system, there is known architectures that the particle group is moved along the direction relative with electrode (substrate), makes the particle group be different from above system (being called system in the plane) and the mixing device that makes up these systems along what the direction of electrode (substrate) moved.

In the electrophoretic particle dispersion liquid according to exemplary, by using the color multiple electrophoresis particle different with charge polarity as mixture, realize that color shows.

[display medium and display unit]

Hereinafter will describe according to the display medium of exemplary and an example of display unit.

Fig. 1 is the synoptic diagram according to the display unit of exemplary.The figure of particle Move Mode when Fig. 2 A and 2B apply voltage for typically showing between the substrate according to the display medium of the display unit of exemplary.

Display unit 10 according to exemplary is taked following form: use according to the electrophoretic particle dispersion liquid of the exemplary particle dispersion that contains dispersion medium 50 and particle group 34 as display medium 12, namely take such form: will be scattered in the dispersion medium 50 as particle group 34 according to the electrophoresis particle of exemplary.

As shown in Figure 1, voltage applying unit 16 and the control unit 18 that applies voltage by display medium 12, to display medium 12 according to the display unit 10 of exemplary formed.

Display medium 12 by as the display base plate 20 of picture display face, at certain intervals in the face of the back substrate 22 of display base plate 20, be used for keeping between the substrate specific interval and be that the distance member 24 of a plurality of cells and the reflective particle group 36 different with the optical reflectance property of the particle group 34 that is closed in each cell are formed with the spatial division between display base plate 20 and the back substrate 22.

Above-mentioned cell refers to by display base plate 20, back substrate 22 and distance member 24 area surrounded.Dispersion medium 50 is sealed in the cell.Particle group 34 is made up of a plurality of particles and is scattered in the dispersion medium 50, and according to the strength of electric field that forms in cell, a plurality of particles pass the space between the reflective particle group 36 and move between display base plate 20 and back substrate 22.

Display medium 12 can be constituted as by such mode each pixel is shown: form distance member 24 with corresponding to each pixel when display medium 12 shows images, and form cell with corresponding to each pixel.

In exemplary, for the purpose of simplifying the description, by paying close attention to a cell exemplary is described.Hereinafter describe each assembly in detail.

At first, will describe by a pair of substrate.

Display base plate 20 has such structure: wherein surface electrode 40 and upper layer 42 stack gradually on support substrate 38.Back substrate 22 has such structure: wherein backplate 46 and upper layer 48 are layered on the support substrate 44.

Display base plate 20 has light transmission, and perhaps display base plate 20 and back substrate 22 all have light transmission.Light transmission in the exemplary refers to that visible light transmittance is 60% or higher.

As the material of support substrate 38 and support substrate 44, for example can enumerate glass and plastics, as pet resin, polycarbonate resin, acrylic resin, polyimide resin, vibrin, Resins, epoxy and polyethersulfone resin.

As the material of surface electrode 40 and backplate 46, for example can enumerate: the oxide compound of indium, tin, cadmium and antimony, composite oxides (as ITO), metal (as gold and silver, copper and mickel) and organic materials (as polypyrrole and Polythiophene).Surface electrode 40 and backplate 46 can be any one in monofilm, hybrid films and the composite membrane of these materials.The thickness of surface electrode 40 and backplate 46 is preferably more than or equals

And be less than or equal to

Backplate 46 and surface electrode 40 can form rectangular or strip.

Surface electrode 40 can be embedded in the support substrate 38.In addition, backplate 46 can be embedded in the support substrate 44.In this case, according to the composition of each particle in the particle group 34, select the material of support substrate 38 and support substrate 44.

Backplate 46 can be separated with back substrate 22 with display base plate 20 separately with surface electrode 40, and is arranged in the outside of display medium 12.

In the above description, display base plate 20 and back substrate 22 all dispose electrode (surface electrode 40 and backplate 46), but can electrode be set in a side, and can carry out driven with active matrix.

In order to carry out driven with active matrix, support substrate 38 and support substrate 44 can arrange the TFT(thin film transistor at each pixel).Preferably on the substrate 22 rather than at display base plate 20 TFT is set overleaf.

Description list surface layer hereinafter.

Upper layer 42 and upper layer 48 are respectively formed on surface electrode 40 and the backplate 46.As the material that is used to form upper layer 42 and upper layer 48, for example can enumerate: acrylic resin and the fluoro-resin of polycarbonate, polyester, polystyrene, polyimide, Resins, epoxy, polymeric polyisocyanate, polymeric amide, polyvinyl alcohol, polyhutadiene, polymethylmethacrylate, copolymerization nylon, UV-curable.

Upper layer 42 and upper layer 48 can be made of above resin and charge transfer material, perhaps can be by the self-supporting resin formation with electric charge transmission property.

Next, distance member is hereinafter described.

Formed by (for example) thermoplastic resin, thermosetting resin, electron beam curable resin, light-cured resin, rubber or metal for the distance member 24 of keeping the spacing between display base plate 20 and the back substrate 22.

Distance member 24 can be incorporated in display base plate 20 or the back substrate 22.In this case, support substrate 38 or support substrate 44 are carried out etched etch processes, laser treatment, used pressing treatment or the printing treatment of the mould of prepared beforehand to carry out above-mentioned incorporating into by being used for.

In this case, any one or both at display base plate 20 and back substrate 22 make distance members 24.

Distance member 24 can be coloured or colourless, but is preferably water white.In this case, use transparent resin such as polystyrene, polyester or acrylic resin.

Preferably, be in the distance member 24 of graininess also for transparent, and except transparent resin (for example polystyrene, polyester or acrylic resin), also use glass particle.

" transparent " refers to that visible light transmittance is 60% or higher.

The reflective particle group is hereinafter described.

Reflective particle group 36 is made up of the reflective particle that the optical reflection characteristic is different from particle group 34, and plays the effect of the reflection part that demonstrates the color that is different from particle group 34.Reflective particle group 36 also has the function as distance member, and it is not disturbing particle to make particle move under situation mobile between display base plate 20 and the back substrate 22.That is, the particle of particle group 34 passes reflective particle group 36 and from back substrate 22 side shiftings to display base plate 20 sides, perhaps from display base plate 20 side shiftings to back substrate 22 sides.The color preferred white of reflective particle group 36 or black is color as a setting, but can be other colors.Reflective particle group 36 can be uncharged particle group (the not particle group that moves according to electric field), perhaps can be charged particle group (the particle group that moves according to electric field).In exemplary, described in uncharged particle group and color and be the reflective particle group 36 under the situation of white, but this not restrictive.

Particle as reflective particle group 36, can enumerate: by with white pigment (as, titanium oxide, silicon oxide, zinc oxide) be scattered in resin (as, polystyrene resin, polyvinyl resin, acrylic resin, polycarbonate resin, plexiglass (PMMA), acrylic resin, phenol resins, formaldehyde condensation products) in and the particle that obtains or resin particle (as, polystyrene particle, polyvinylnaphthaleneand particle, two trimeric cyanamide particle).When the particle except white particles is put on the particle of reflective particle group 36, can use the pigment that comprises required color or the above-mentioned resin of dyestuff.Can exemplify the RGB and YMC pigment or the dyestuff that are generally used in printing-ink or the color toner.

For sealing reflective particle group 36 between substrate, for example, adopt ink jet method.Under the situation of fixation reflex particle group 36, melt with the upper layer with the particle in the reflective particle group 36 with 36 sealings of reflective particle group and with post-heating (if necessary by compacting), keep the spacing of particle simultaneously.

Other structures of display medium are hereinafter described.

The resolving power of the cell size in the display medium 12 and display medium 12 is closely related.Cell size is more little, and the resolving power of the image that shows on the display medium 12 is more high.Usually, in the face of the display base plate 20 of display medium 12 on the direction length of cell for more than or equal to 10 μ m and be less than or equal to 1mm.

Content (quality %) with respect to the total amount in the cell, particle group 34 is not particularly limited, as long as can obtain required tone.As display medium 12, it is effective regulating this content by the thickness (distance between display base plate 20 and the back substrate 22) of cell.That is, in order to obtain required tone, cell is more thick, and then content is more low, and cell is more thin, and then content can be more high.Usually, this content is more than or equal to 0.01 quality % and is less than or equal to 50 quality %.

In order to make display base plate 20 and back substrate 22 fixed to one another by distance member 24, adopt mounting block, as combination, anchor clamps, the clip of screw bolt and nut, be used for fixing framework.Also can use such as fixing means such as tackiness agent, heat fusion and ultrasonic wave joints.

The display medium 12(of Gou Chenging is for example like this) be used for: wherein store and rewrite the bulletin board, circulation plates, electronic whiteboard, billboard, signboard, flashing indicator, Electronic Paper, electronic newspaper, electronic publication of image and at duplicating machine and printer filing paper commonly used.

As indicated above, form (referring to Fig. 1) according to voltage applying unit 16 and control unit 18 that the display unit 10 of exemplary applies voltage by display medium 12, to display medium 12.

Surface electrode 40 and backplate 46 are electrically connected with voltage applying unit 16.In exemplary, the situation that wherein surface electrode 40 and backplate 46 all are electrically connected with voltage applying unit 16 has been described, but one in surface electrode 40 and the backplate 46 can ground connection, and another person can be connected with voltage applying unit 16.

Voltage applying unit 16 is connected with control unit 18 can transmit with the mode that receives signal.

Control unit 18 is constructed to minicomputer, and it comprises the CPU(central processing unit that drives for this device of holistic management), be used for the RAM(random access memory of temporary transient storage several data) and wherein store the various programs ROM(read-only storage of (as being used for the sequence of control of this device integral body of control) in advance).

Voltage applying unit 16 is that its control according to control unit 18 applies voltage to surface electrode 40 and backplate 46 for the voltage bringing device that applies voltage to surface electrode 40 and backplate 46.

The function of display unit 10 is hereinafter described.Driving according to control unit 18 illustrates this function.

The particle group 34 that wherein is enclosed in the display medium 12 is described by the charged situation that becomes straight polarity.In addition, be transparent to dispersion medium 50 wherein and reflective particle group 36 describes for the situation of white.That is, in exemplary, to display medium 12 demonstrate color that the movement owing to particle group 34 shows and reflective particle group 36 display white as a setting the situation of color describe.

Driving when for convenience's sake, being attached to back substrate 22 1 sides from particle group 34 is described.

At first, to voltage applying unit 16 output drive signals and continue predetermined time, this signal demonstrates and applies voltage and make surface electrode 40 become negative pole and backplate 46 becomes positive pole.From the state shown in Fig. 2 A, the voltage increase that applies between electrode and the voltage that applies are higher than threshold voltage (thus, surface electrode 40 becomes negative pole and change in concentration finishes) time, state with the aggregation force reduction, constitute the particle of the charged particle group 34 that becomes straight polarity to display base plate 20 side shiftings, and arrive display base plate 20(referring to Fig. 2 B).

After applying the voltage end between the electrode, particle group 34 is limited in display base plate 20 sides, and under the white situation as a setting of reflective particle group 36, the color that is shown by particle group 34 is by the color of Visual Confirmation for the display medium 12 seen from display base plate 20.

Secondly, to voltage applying unit 16 output drive signals and continue predetermined time, this signal demonstrates and applies voltage and make surface electrode 40 become positive pole and backplate 46 becomes negative pole.The voltage increase that applies between electrode and the voltage that applies are higher than threshold voltage (thus, surface electrode 40 becomes positive pole and change in concentration finishes) time, state with the aggregation force reduction, constitute the particle of the charged particle group 34 that becomes straight polarity to display base plate 20 side shiftings, and arrive display base plate 20(referring to Fig. 2 A).

After applying the voltage end between the electrode, particle group 34 is limited in back substrate 22 sides.On the other hand, the white of reflective particle group 36 is by the color of Visual Confirmation for the display medium 12 seen from display base plate 20.The particle group 34 particle group 36 that is reflected is blocked, and becoming is difficult to by Visual Confirmation.

The voltage application time is stored in the storer (as ROM) in advance as the data that are illustrated in voltage application time when applying voltage in the driving process, has omitted the figure of control unit 18 inside.Read the data of expression voltage application time during operation.

Therefore, in the display unit 10 according to exemplary, when particle group 34 arrives and adheres to when gathering display base plate 20 or back substrate 22, show.

In display medium 12 and display unit 10 according to exemplary, such form has been described: thus display base plate 20 arrange surface electrode 40 and overleaf substrate 22 arrange backplate 46 between electrode (namely, between substrate) apply voltage, and make particle group 34 mobile to show between substrate, still be not limited thereto form.For example, such form also is fine: surface electrode 40 is set and at distance member electrode is set at display base plate 20, apply voltage between electrode, and make particle group 34 mobile between display base plate 20 and distance member, thereby realize showing.

In display medium 12 and display unit 10 according to exemplary, described and used a kind of (a kind of color) particle group as the situation of particle group 34, but this is not restrictive, can use two or more (two or more colors) particle groups.

Particularly, for example, can exemplify such form: as particle group 34, use positively charged the first particle group, the electronegative second particle group and positively charged and threshold voltage be different from the 3rd particle group with greater particle size of the particle of the first particle group.

[embodiment]

Reference example is described in further detail the present invention, but the present invention is confined to this never in any form.In an embodiment, unless otherwise indicated, " part " and " % " refers to " mass parts " and " quality % ".

[embodiment 1]

By in water, add 45 mass parts as core particle with the styrene/acrylic resin X-1202L(of resin by the preparation of Seiko PMC company), 5 mass parts as nitrogen-containing heterocycle compound by the melamine compound NIKALAC MW-390(of (B)-2 expression by the preparation of Sanwa KCC) and 50 mass parts as the green pigment H525F(of tinting material by the preparation of Sanyo Color Works Co., Ltd.), make totally be 15 quality %, thus the preparation aqueous liquid dispersion.

Then, with the aqueous liquid dispersion of gained as disperse phase, with silicon oil solution (making by the tensio-active agent KF-6028 (by the preparation of Shin-Etsu KCC) that in silicone oil KF-96-2CS (by the preparation of Shin-Etsu KCC), adds 1 quality %) as external phase, with 10/1(external phase/disperse phase) mass ratio mix, and with this mixture of homogenizer emulsification, thereby preparation emulsion.

Subsequently, with the emulsion that obtains in vaporizer in 60 ℃ down dry 6 hours removing the water in the emulsion, thereby obtain the core particle dispersion liquid.The median size of the core particle of gained is 0.6 μ m, (index of expression monodispersity: the variation coefficient: CV (%)=(σ/D) x100 (σ: standard deviation, D: median size)) is 25% to the C.V. value.

Use centrifuge separator, wash the core particle that is scattered in the dispersion liquid with silicone oil, thereby prepared the core particle dispersion liquid of 1 quality %.

The preparation multipolymer is as the tectum resin, and it contains: the SILAPLANE FM-0721(as the polymeric component with organosilicon chain is prepared by Chisso company), 2-(acryloxy) ethyl-trimethyl salmiac (AOETMA) and methacrylic acid 2-hydroxyl ethyl ester (HEMA) as the polymeric component with charging property group, isocyanate-monomer (the isocyanate-monomer KARENZ MOI-BP(with isocyanate group of sealing is prepared by Showa Denko K.K.) as the polymeric component with reactive group (crosslinked group), and as the MMA(methyl methacrylate of other polymeric components) (in the following table 2 mol ratio being shown).

Then, the tectum that 2g is obtained is added into the IPA(Virahol with resin), thus prepare the IPA solution of 10 quality %.

Subsequently, the IPA solution of the 10 quality % that 20g is obtained is added in the 20g core particle dispersion liquid and stirs, in vaporizer, descend dry 1 hour to remove the IPA in the core particle dispersion liquid in 60 ℃ subsequently, thereby tectum is separated out on core particle with resin, obtains thus wherein to be formed with tectal granular disintegration on the core particle surface.

Subsequently, the core particle dispersion liquid was heated 1 hour down at 130 ℃, make to constitute core particle and tectal resin crosslinks.

Obtain the dispersion liquid of such electrophoresis particle by above operation, wherein be formed with tectum on the surface of core particle.

Use centrifuge separator, wash the electrophoresis particle that is scattered in the core particle dispersion liquid with silicone oil.

[embodiment 2 to 9]

Obtain electrophoresis particle and electrophoretic particle dispersion liquid according to the mode identical with embodiment 1, difference is, changes core particle and tectal composition according to following table 1 and table 2.

But, in embodiment 5 and 6, do not carry out the thermal treatment that constitutes core particle and tectal resin crosslinks be used to making.

In embodiment 7,8 and 9, as the polymeric component of tectum with resin, use methacrylic acid stearyl (SMA) to substitute as the polymeric component with alkyl chain and have the component of organosilicon chain.

[comparative example 1]

Obtain electrophoresis particle and electrophoretic particle dispersion liquid according to the mode identical with embodiment 1, difference is, mismatches nitrogen-containing heterocycle compound when the preparation core particle.

[comparative example 2]

After preparing core particle according to the mode identical with embodiment 1, with this dispersion of particles liquid 130 ℃ down heating made the resin crosslinks that constitute core particle obtaining electrophoresis particle in 1 hour, and obtain this dispersion of particles liquid.

[comparative example 3]

Obtain electrophoresis particle and dispersion liquid thereof according to the mode identical with embodiment 1, difference is, mismatches nitrogen-containing heterocycle compound.

But, as the polymeric component of tectum with resin, use methacrylic acid stearyl (SMA) to substitute the polymeric component with organosilicon chain as the polymeric component with alkyl chain.The mass parts that constitutes the resin of core particle is become 50 mass parts.

[evaluation]

Regulate dispersion liquid and make white particles be included among the external phase KF-96-2CS with the amount of 20 quality % and electrophoresis particle (cyan particles) amount with 1 quality %, thereby obtain electrophoretic particle dispersion liquid.

According to being prepared as follows white particles.

The preparation of-white particles-

Add the KF-96-1CS(of 2-vinyl naphthalene, 240 mass parts of SILAPLANE FM-0721,45 mass parts of 45 mass parts in the flask by the preparation of Shin-Etsu KCC) and the lauroyl peroxide of 2 mass parts, when stirring, make nitrogen with 0.2 liter/minute flow velocity bubbling to carry out deoxidation, subsequently in oil bath in 70 ℃ down heating 10 hours to obtain the white particles dispersion liquid.By the centrifugal particle dispersion precipitation that obtains that makes, remove supernatant liquor and add the KF-96-2CS of 400ml, and make liquid return to dispersion state by the ultrasonic wave radiation.Repeat this operation 3 times to wash the displacement with KF-96-2CS, obtain the white particles dispersion liquid.

The median size of the white particles that obtains is that 0.5 μ m and C.V. value are 10%.

In addition, this white powder not can because of apply ± the 20V electric field moves.

Then, be enclosed in a pair of glass substrate (in such cell: wherein, between a pair of glass substrate, get involved the spacer (distance member) that 50 μ m are arranged) that wherein is formed with indium tin oxide (ITO) electrode with the preparation facilities sample by the electrophoretic particle dispersion liquid with gained.Described spacer is to form like this: rotary coating CYTOP(CTL809M on the electrode forming surface of a side glass substrate, by the preparation of Asahi Glass Co., Ltd.), and under 200 ℃, heated 4 hours.

Use the device sample that obtains, between electrode, apply ± voltage of 15V by function generator (power supply that NF company makes is driven by the prepared Lab VIEW of National Instruments), and with amperometer (manufacturing of Keithley company) and optical measurement instrument (USB2000, Ocean Optics company makes) measure the ratio that exists of opposite polarity particle in carried charge, threshold voltage and the electrophoresis particle of electrophoresis particle, literary composition specific as follows is described.

-carried charge-

Apply the square wave of 0V to 15V and with the carried charge addition when current value becomes constant, thereby obtain the carried charge (initial strip electric weight) of electrophoresis particle.

Electrophoretic particle dispersion liquid is placed the screw socket bottle and after preserving for 1 week under 60 ℃, measures the carried charge (carried charge after for some time) of electrophoresis particle in an identical manner again.

-threshold voltage-

Under 0.05Hz, apply the triangular wave of 0V to 15V, and adopt optical measurement instrument to record the peaked voltage of reflectivity at 90% o'clock, and with this voltage as threshold voltage, obtain the threshold voltage (initial threshold voltage) of electrophoresis particle thus.

Electrophoretic particle dispersion liquid is placed the screw socket bottle and after preserving for 1 week under 60 ℃, measures the threshold voltage (threshold voltage after for some time) of electrophoresis particle in an identical manner again.

-opposite polarity particle exist ratio-

By carrying out the calibration of the black in white and the dark with standard model, that adopts that optical measurement instrument measures opposite polarity particle in the electrophoresis particle exists ratio (initially having ratio).

With electrophoretic particle dispersion liquid place the screw socket bottle and 60 ℃ down preserved for 1 week after, that measures opposite polarity particle in the electrophoresis particle in an identical manner again exists ratio (after for some time opposite polarity particle exist ratio).

The composition of table 1 core particle

The tectal resin of table 2 is formed

Table 3

From The above results as can be seen, compare with comparative example, carried charge and threshold voltage are all higher among the embodiment.

Can also see, compare with comparative example that the opposite polarity particle exists ratio low among the embodiment.

Abbreviation in table 1 and the table 2 is as follows.

-core particle resin-

X-1202L:[X-1202L (being made by Seiko PMC Corporation), weight-average molecular weight: 20,000]

-nitrogen-containing heterocycle compound-

MW-390: the melamine compound [NIKALAC MW-390 (by the preparation of Sanwa KCC)] that exemplary compounds (B)-2 formula is represented

-tinting material-

H525F: green pigment [H525F (by the preparation of Sanyo Color Co., Ltd.)]

-tectum resin-

FM-0721:[SILAPLANE FM-0721 (by the preparation of Chisso company), weight-average molecular weight Mw:5,000, structural formula (1), wherein R ₁Be methyl, R ₁' for butyl, n are 68, x is 3]

SMA: methacrylic acid octadecane ester

MAA: methacrylic acid

HEMA: methacrylic acid 2-hydroxyl ethyl ester

MOI-BP: have the isocyanate-monomer methacrylic acid 2-[(3 of the isocyanate group of sealing, 5-dimethyl pyrazole base) carbonylamino] ethyl ester [Karenz MOI-BP (being made by Showa Denko K.K.)]

MMA: methyl methacrylate

AOETMA:2-(acryloxy) ethyl-trimethyl salmiac.

Claims (13)

1. electrophoresis particle, contain:

By the core material particle that composition forms, described composition contains resin, nitrogen-containing heterocycle compound and tinting material, and this nitrogen-containing heterocycle compound has any one in imino-, methylol and the alkoxy methyl and has the heterocycle of nitrogen atom in molecule.

2. electrophoresis particle according to claim 1,

Wherein said nitrogen-containing heterocycle compound is selected from the group that is made of melamine compound and guanamines compound, has in imino-, methylol and the alkoxy methyl any one in each comfortable molecule of described melamine compound and guanamines compound.

3. electrophoresis particle according to claim 1,

The surface-coated cap rock of described core material particle covers,

Wherein said tectum is formed by the composition that contains resin, and described resin has the close dispersion medium part that dissolves in the dispersion medium that wherein is dispersed with described electrophoresis particle and is insoluble to thin dispersion medium part in the dispersion medium that wherein is dispersed with described electrophoresis particle.

4. electrophoresis particle according to claim 3,

Described tectum is formed by the composition that contains copolymer resin, the polymeric component that wherein said multipolymer comprises the polymeric component with organosilicon chain at least or has the polymeric component of alkyl chain and have the charging property group.

5. electrophoresis particle according to claim 1,

Wherein based on the total amount of described core material particle, the content of described nitrogen-containing heterocycle compound is more than or equal to 0.5 quality % and is less than or equal to 50 quality %.

6. electrophoresis particle according to claim 1,

Wherein said core material particle is the core material particle that the resin crosslinks product by the described composition that contains resin, nitrogen-containing heterocycle compound and tinting material constitutes.

7. electrophoresis particle according to claim 3,

Wherein said tectum is the tectum that the resin crosslinks product by the described composition that contains described resin constitutes.

8. electrophoretic particle dispersion liquid comprises:

Dispersion medium and

Be scattered in the electrophoresis particle in the described dispersion medium,

Wherein said electrophoresis particle is electrophoresis particle according to claim 1.

9. electrophoretic particle dispersion liquid according to claim 8,

Wherein said dispersion medium contains the low solvent of specific inductivity.

10. display medium comprises:

A pair of substrate, wherein at least one has light transmission, and

Electrophoretic particle dispersion liquid according to claim 8, it is closed between the described a pair of substrate.

11. a display medium comprises:

Pair of electrodes, wherein at least one has light transmission, and

Zone with electrophoretic particle dispersion liquid according to claim 8, described zone is closed between the described pair of electrodes.

12. a display unit comprises:

Display medium according to claim 10, and

Between a pair of substrate of described display medium, apply the voltage applying unit of voltage.

13. a display unit comprises:

Display medium according to claim 11, and

Between the pair of electrodes of described display medium, apply the voltage applying unit of voltage.

Images